The complex immunogenetic basis of systemic lupus erythematosus

Systemic lupus erythematosus: pathogenesis and targeted therapy

Systemic lupus erythematosus (SLE) is a multifaceted autoimmune disorder characterized by dysregulated immune responses and autoantibody production, which affects multiple organs and varies in clinical presentation and disease severity. The development of SLE is intricate, encompassing dysregulation within the immune system, a collapse of immunological tolerance, genetic susceptibilities to the disease, and a variety of environmental factors that can act as triggers. This review provides a comprehensive discussion of the pathogenesis and treatment strategies of SLE and focuses on the progress and status of traditional and emerging treatment strategies for SLE. Traditional treatment strategies for SLE have mainly employed non-specific approaches, including cytotoxic and immunosuppressive drugs, antimalarials, glucocorticoids, and NSAIDs. These strategies are effective in mitigating the effects of the disease, but they are not a complete cure and are often accompanied by adverse reactions. Emerging targeted therapeutic drugs, on the other hand, aim to control and treat SLE by targeting B and T cells, inhibiting their activation and function, as well as the abnormal activation of the immune system. A deeper understanding of the pathogenesis of SLE and the exploration of new targeted treatment strategies are essential to advance the treatment of this complex autoimmune disease.

HLA-DRB1*04 as a Risk Allele to Systemic Lupus Erythematosus and Lupus Nephritis in the Malay Population of Malaysia

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease afflicting multiple organs. Lupus nephritis (LN) is a serious complication of SLE and remains a major cause of mortality and morbidity. Curative therapy remains unavailable as etiology from genetic and environmental factors is still unclear. The present study was conducted to elucidate the link between HLA-DRB1 gene polymorphisms with SLE and LN through clinical and laboratory/biological presentations in a population of Malaysian Malay females with SLE. A total of 100 Malay female SLE patients inclusive of 70 SLE patients without LN and 30 patients with LN were included in this study. HLA-DRB1 allele examination in SLE patients was performed using PCR-SSO, and the alleles' frequencies were compared with 951 publicly available datasets representing Malay healthy controls in Malaysia. Cytokines and free radical levels were detected by ELISA and bead-based multiplexed Luminex assays. The association between HLA-DRB1 alleles with clinical and serological manifestations and immune mediators was analyzed using different statistical approaches whenever applicable. Our study showed that HLA-DRB1^*0405, HLA-DRB1^*1502, and HLA-DRB1^*1602 were associated with the increased risk of SLE while HLA-DRB1^*1201 and HLADRB1^*1202 alleles were associated with a lower risk of SLE development. Furthermore, HLA-DRB1^*04 showed significant association to LN and arthritis while HLA-DRB1^*15 was significantly associated with oral ulcer in Malay SLE patients. Association analysis of HLA-DRB1^*04 with clinical and biological factors revealed that HLA-DRB1^*04 was significantly associated with Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) scores, anti-nuclear antibody (ANA), C-reactive protein (CRP) in the blood, and total protein in the urine. SLE carriers with the HLA-DRB1^*04 allele were significantly correlated to the increased levels of cytokines (IFN-y, GM-CSF, IL-17F, IL-18, IL-21, and VEGF) and were significantly showing negative correlation to IL-5 and free radicals (LPO and catalase enzyme) levels compared to SLE carriers without HLA-DRB1^*04 allele. The results suggested that disease severity in SLE may be determined by HLA-DRB1 alleles. The risk of HLA-DRB1^*04 allele with LN was supported by the demonstration of an intense inflammatory response in Malay SLE patients in Malaysia. More studies inclusive of a larger and multiple SLE cohorts in the future are warranted to validate these findings.

Association of AIRE (rs2075876), but not CTLA4 (rs231775) polymorphisms with systemic lupus erythematosus

BACKGROUND

The AIRE (rs2075876) and CTLA4 (rs231775) variants have a crucial function in controlling the negative selection and suppression of T lymphocytes. Numerous reports studied the association of AIRE and CTLA4 variants with different autoimmune disorders, but with inconclusive conclusions. The main purpose of this work is to evaluate the association of these two variants with SLE susceptibility among Egyptian patients.

SUBJECTS AND METHODS

A total of 247 participants (100 SLE patients and 147 healthy controls) were enrolled in this case-controlled study. The genomic DNA of these dual variants was genotyped using the TaqMan genotyping method.

RESULTS

The AIRE (rs2075876) variant conferred protection against developing SLE disease under allelic [A allele vs. G allele; OR = 0.16, 95%CI = 0.09-0.28], and dominant [GA + AA vs. GG; OR = 0.14, 95%CI = 0.05-0.34] models. Moreover, patients with AIRE rs2075876 (A/A) genotype revealed a statistically significant with lower levels of complement 3 (p-value = 0.007). Nonetheless, the CTLA4 (rs231775) variant was not associated with increased risk of SLE under all genetic association models (p-value > 0.05). However, CTLA4 rs231775 (G/G) genotype observed significant difference with recurrent infection and hematuria.

CONCLUSIONS

Our findings indicated that the AIRE (rs2075876) variant conferred protection against developing SLE disease, but not the CTLA4 (rs231775) variant.

Pentraxin 3: A promising therapeutic target for autoimmune diseases

Pentraxin 3 (PTX3) is a prototypic humoral soluble pattern recognition molecule that exerts a pivotal role in innate immune response and inflammation, as well as in tissue damage and remodeling. Recently, emerging evidence has revealed that PTX3 is involved in the occurrence and development of various autoimmune diseases, such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), ankylosing spondylitis (AS), systemic sclerosis (SSc), inflammatory bowel disease (IBD), multiple sclerosis (MS) and psoriasis, etc. In this review, we have succinctly summarized the complex immunological functions of PTX3 and mostly focused on recent findings of the pleiotropic activities played by PTX3 in the pathogenesis of autoimmune diseases, aiming at hopefully offering possible future therapeutic alternatives.

Simultaneous bilateral optic neuritis in China: clinical, serological and prognostic characteristics

PURPOSE

To analyse the clinical characteristics of simultaneous bilateral ON patients in China.

METHODS

This retrospective study was done on 51 primary bilateral ON patients between April 2008 and July 2016 at the Chinese People's Liberation Army General Hospital. Fifty eight primary unilateral ON patients formed the control group. Demographic data, clinical course, serum autoantibody status, connective tissue disorders, magnetic resonance imaging and visual functions were compared.

RESULTS

The mean age at disease onset in the bilateral group was younger than that of the unilateral group (p = 0.001). Cerebrospinal fluid (CSF) total cell count and CSF total protein were significantly higher in the bilateral group (p = 0.001, p = 0.025). Aquaporin-4 (AQP4) antibodies were detected in 39% and 21% of the bilateral and unilateral patients, respectively (p = 0.03). Twenty two percent of the bilateral patients fulfilled the diagnosis of neuromyelitis optica (NMO); 7% in the unilateral group did so (p = 0.03). Serum autoantibodies (ANA, SSA, SSB, etc.) were found in 49% of the bilateral patients and 29% of the unilateral patients (p = 0.035). After treatment, the bilateral patients were significantly more prone to severe visual disability eventually than their unilateral counterparts (p = 0.002). Patients with MOG-IgG (myelin oligodendrocyte glycoprotein-IgG) represented 26% of the patients negative for AQP4-IgG. Myelin oligodendrocyte glycoprotein-IgG (MOG-IgG) sero-positive patients were more likely to recover than the other patients (p < 0.001).

CONCLUSION

Simultaneous bilateral ON is a severe disorder closely related to serum AQP4-IgG and MOG-IgG, which are more likely to involve younger people and incur severe visual disability eventually. Myelin oligodendrocyte glycoprotein-IgG (MOG-IgG) sero-positive patients have higher risk of ON relapses and better visual prognosis.

Anti-pentraxin 3 auto-antibodies might be protective in lupus nephritis: a large cohort study

Objectives: Anti-pentraxin 3 (PTX3) auto-antibodies were found to be associated with the absence of renal involvement in systemic lupus erythematosus (SLE). This study is to investigate the prevalence of anti-PTX3 auto-antibodies and their clinical significance based on a large Chinese lupus nephritis cohort.

Methods: One hundred and ninety-six active lupus nephritis patients, 150 SLE patients without clinical renal involvement, and 100 healthy controls were enrolled. Serum anti-PTX3 auto-antibodies and PTX3 levels were screened by enzyme-linked immunosorbent assay (ELISA). The associations between anti-PTX3 auto-antibodies and clinicopathological parameters in lupus nephritis were further analyzed.

Results: Anti-PTX3 auto-antibodies were less prevalent in active lupus nephritis patients compared with SLE without renal involvement (19.4% (38/196) versus 40.7% (61/150), p < .001). The serum levels of anti-PTX3 auto-antibodies were negatively correlated with proteinuria in lupus nephritis (r = −.143, p = .047). The levels of proteinuria, serum creatinine, and the prevalence of thrombotic microangiopathy were significantly higher in patients with higher PTX3 levels (≥3.207 ng/ml) and without anti-PTX3 auto-antibodies compared with patients with lower PTX3 levels (<3.207 ng/ml) and with anti-PTX3 auto-antibodies (4.79 (3.39–8.28) versus 3.95 (1.78–7.0), p = .03; 168.84 ± 153.63 versus 101.44 ± 47.36, p = .01; 34.1% (14/41) versus 0% (0/9), p = .04; respectively).

Conclusion: Anti-PTX3 auto-antibodies were less prevalent in active lupus nephritis patients compared with SLE without renal involvement and associated with less severe renal damage, especially with the combined evaluation of serum PTX3 levels.

DUSP23 is over-expressed and linked to the expression of DNMTs in CD4+ T cells from systemic lupus erythematosus patients

We evaluated the transcriptional expression of dual-specificity protein phosphatase 23 (DUSP23) in CD4⁺ T cells from 30 systemic lupus erythematosus (SLE) patients and 30 healthy controls. DUSP23 mRNA levels were considerably higher in the patient group: 1490 ± 1713 versus 294·1 ± 204·2. No association was found between DUSP23 mRNA expression and the presence of typical serological and clinical parameters associated with SLE. Meaningful statistical values were obtained in the patient group between the levels of DUSP23 and integrin subunit alpha L (ITGAL), perforin 1 (PRF1) and CD40L. Similarly, transcript levels of different DNA methylation-related enzymes [DNA methylation-related enzymes (DNMT1, DNMT3A, DNMT3B, MBD2, and MBD4)] were also correlated positively with the expression of DUSP23. In an attempt to counteract the hypomethylation status of the promoters of certain genes known to be over-expressed in SLE, it is possible that DUSP23 acts as a negative regulatory mechanism which ultimately silences the transcription of these epigenetically regulated genes by triggering an increase in the expression of different DNMTs.

Pentraxin 3 Is Closely Associated With Tubulointerstitial Injury in Lupus Nephritis: A Large Multicenter Cross-Sectional Study

Lupus nephritis always elicits immune inflammatory tissue damages in kidney. Pentraxin 3 (PTX3), mainly produced at inflammatory sites, is known to be involved in the regulation of the innate immunity system. The aim of this study was to investigate the serum and urine levels of PTX3, and the expression of PTX3 in renal tissues in lupus nephritis patients from a large Chinese cohort.The study used cross-sectional survey and 288 active lupus nephritis patients, including discovery cohort and validation cohort, 115 systemic lupus erythematosus (SLE) patients without clinical renal involvement and 46 healthy controls were enrolled. Serum and urine PTX3 were screened by enzyme-linked immunosorbent assay (ELISA). The renal deposition of PTX3 was detected by immunohistochemistry and immunofluorescence.The average level of serum PTX3 in the discovery cohort of lupus nephritis was significantly higher than that in nonrenal involvement SLE group and normal controls (P < 0.001, P < 0.001, respectively), which was confirmed by the validation cohort. Serum PTX3 levels of 15 lupus nephritis patients in remission decreased significantly compared with that in active phase. Serum PTX3 levels were significantly higher in patients with hematuria (P = 0.014), leucocyturia (P = 0.002), acute renal failure (P = 0.001), and nephrotic syndrome (P = 0.036). There were significant correlations between serum PTX3 levels and Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) scores, serum creatinine value, renal pathological activity indices, and serum complement 3 (C3) in active lupus nephritis patients. The urinary PTX3 levels were significantly higher in active lupus nephritis patients compared with patients in remission and normal controls (P = 0.011, P = 0.008, respectively). There were significant associations between urinary PTX3 levels and multiple indices of tubulointerstitial lesions, including urinary KIM-1 (r = 0.368, P = 0.016), neutrophil gelatinase-associated lipocalin (NGAL) (r = 0.320, P = 0.039), microalbumin (r = 0.621, P = 0.003), transferring (r = 0.451, P = 0.040) levels and renal pathological indices scores, especially interstitial inflammation (r = 0.349, P = 0.025) in active lupus nephritis patients. A significant correlation was found between serum and urine PTX3 levels (r = 0.431, P = 0.006). PTX3 staining was mainly observed in tubulointerstitial areas of patients with lupus nephritis, and immunofluorescence study showed that PTX3 could colocalize with fibroblast in interstitium.Circulating and local PTX3 levels were significantly increased in patients with active lupus nephritis and might be a biomarker for the disease progression, especially of tubulointerstitial injury.

Genetic polymorphisms of interleukin 6 and interleukin 10 in Egyptian patients with systemic lupus eythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disease. Cytokine gene polymorphisms play an important role in SLE. Thus, this study aimed to investigate the associations between interleukin 6 (IL-6) and interleukin 10 (IL-10) promoter single-nucleotide polymorphisms (SNPs) and their susceptibility to SLE and the implications for plasma levels. We genotyped IL-6-174G/C (rs1800795) using mutagenically separated polymerase chain reaction (MS-PCR) and IL-10-1082G/A (rs1800896) and -819C/T (rs1800871) using sequence specific primer polymerase chain reaction (SSP-PCR) in 100 Egyptian patients and 119 controls. The plasma levels of IL-6 and IL-10 were measured by enzyme-linked immunosorbent assay (ELISA). There was significant increase in the frequency of IL-6 (-174) GG genotype ( P < 0.05) and G allele ( P < 0.01) compared to controls. A significant increase in the distribution of IL-10 (-1082G/A) GG ( P < 0.05) and AA ( P < 0.05) genotypes and a significant reduction in the frequency of GA genotype ( P < 0.05) was found in SLE patients. The mean serum concentration of IL-6 ( P < 0.001) and IL-10 ( P < 0.001) was significantly elevated in SLE patients compared to healthy controls. There was no  significant association of the most common clinical findings and IL-6 and IL-10 gene polymorphisms in SLE patients. In conclusion, our preliminary study indicated that both GG genotype and G allele of IL-6 (-174G/C) could be considered as risk factors for SLE. In addition, the polymorphisms at IL-10 (-1082 G/G and AA) may play a role in SLE susceptibility in Egyptian patients. Larger prospective studies are needed to confirm our findings.

Clinical, serologic, and immunogenetic characterization (HLA-DRB1) of late-onset lupus erythematosus in a Colombian population

INTRODUCTION

Late-onset systemic lupus erythematosus (SLE) represents a specific subgroup that is defined as onset after 50 years of age. Late-onset lupus may have a different clinical course and serological findings, which may delay diagnosis and timely treatment.

OBJECTIVES

The objective of this paper is to determine the clinical, serologic, and immunogenetic differences among Colombian patients with late-onset SLE versus conventional SLE patients.

METHODOLOGY

This was a cross-sectional study in a Colombian population. Patients and their medical records were analyzed from the services of Rheumatology in Bogotá and met the criteria for SLE, according to the American College of Rheumatology (ACR) revised criteria for the classification of SLE.In a reference group of late-onset SLE patients (98 participants, with an onset after 50 years of age) and a group of conventional SLE patients (72 participants, with an onset of age of 49 years or less), multiple clinical variables (age, clinical criteria for lupus, alopecia, weight loss, fever, Raynaud's phenomenon) and multiple serological variables (blood count, blood chemistry profile, autoantibodies) were analyzed. Additionally, the HLA class II (DRB1) of all the patients was genotyped, including an additional group of patients without the autoimmune disease. Statistical analysis was performed using the STATA 10.0 package.

RESULTS

In the group of late-onset lupus, there was a higher frequency of pleurisy (p = 0.002), pericarditis (p = 0.026), dry symptoms (p = 0.029), lymphopenia (p = 0.007), and higher titers of rheumatoid factor (p = 0.001) compared with the group of conventional SLE. Late-onset SLE patients had a lower seizure frequency (p = 0.019), weight loss (p = 0.009), alopecia (p < 0.001), and Raynaud's phenomenon (p = 0.013) compared to the conventional SLE group. In late-onset SLE, HLA DR17 (DR3) was found more frequently compared with individuals without autoimmune disease (OR 3.81, 95% CI 1.47 to 10.59) (p = 0.0016).

CONCLUSION

In the Colombian SLE population analyzed, there may be a probable association of several clinical and serologic variants, which would allow the differentiation of variables in the presentation of the disease among patients with late-onset SLE vs. conventional SLE.

Relation between HLA typing and clinical presentations in Systemic Lupus Erythematosus patients in Al-Qassim region, Saudi Arabia

BACKGROUND

Systemic lupus erythematosus (SLE) is a disease with diverse clinical presentations due to interaction between genetic and environmental factors. SLE is associated worldwide with polymorphisms at various loci, including the major histocompatibility complex (MHC), although inconsistencies exist among these studies.

AIMS

This study was carried out to investigate, the association of HLA-DRB1, DRB3, DRB4, DRB5, and DQB1 alleles in SLE patients and clinical presentations at Qassim, Saudi Arabia.

METHODS

Fifty one patients with SLE-84.3% of whom had kidney involvement were studied in a case control study for HLA-DRB1, DRB3, DRB4, DRB5, and DQB1.

RESULTS

It was found that DRB3 is a protective gene among Saudi's against SLE, HLA DRB3, HLA DRB1*11 frequency was increased in patients with serositis with a p value of (0.004), (0.047) respectively, increased frequency of HLA DQB1*3 among SLE patients with skin manifestations with a p value of (0.041), the frequency of HLA DRB1*15 alleles was increased among SLE patients with nephritis with a p value of (0.029), the frequency of HLA DRB1*11 among those with hematological manifestations with a p value of (0.03) and the frequency DRB1*10 was found to be increased among SLE patients with neurological manifestations with a p value of (0.002).

CONCLUSION

In contradistinction to what have been found among other populations DRB3 is a protective gene among Saudi's against SLE. No evidence for a role of the HLA-DRB1, DRB4, DRB5, DQB1 alleles. There was an increased HLA DRB3 frequency with serositis, DQB1*3 skin manifestations, HLA DRB1*15 with nephritis, DRB1*10 with hematological manifestations and DRB1*11 with neurological manifestations.

Frequency of autoantibodies and connective tissue diseases in Chinese patients with optic neuritis

Background

Optic neuritis (ON) is often associated with other clinical or serological markers of connective tissue diseases (CTDs). To date, the effects of autoantibodies on ON are not clear.

Purpose

To assess the prevalence, clinical patterns, and short outcomes of autoantibodies and Sjögren’s syndrome (SS) involvement in Chinese ON patients and evaluate the relationship between ON, including their subtypes, and autoantibodies.

Methods

A total of 190 ON patients were divided into recurrent ON (RON), bilateral ON (BON), and isolated monocular ON (ION). Demographic, clinical, and serum autoantibodies data were compared between them with and without SS involvement. Serum was drawn for antinuclear antibody (ANA), extractable nuclear antigen antibodies (SSA/SSB), rheumatoid factor (RF), anticardiolipin antibodies (ACA), and anti-double-stranded DNA antibody (A-ds DNA), anticardiolipin antibody (ACLs), anti-β2-glycoprotein I (β2-GPI) and Aquaporin-4 antibodies (AQP4-Ab). Spectral-domain optical coherence tomography (SD-OCT) was used to evaluate the atrophy of the optic nerve.

Results

68 patients (35.79%) had abnormal autoantibodies, 26(13.68%) patients met diagnostic criteria for CTDs, including 15(7.89%) patients meeting the criteria for SS. Antibodies including SSA/SSB 23 (30.26%) (p1 and p 2<0.001) and AQP4–Ab10 (13.16%) (p1 = 0.044, p2 = 0.01) were significantly different in patients in the RON group when compared with those in the BON (P1 = RON VS ION) and ION (p2 = RON VS ION) groups. SS was more common in RON patients (p1 = 0.04, p2 = 0.028). There was no significant difference between SSA/SSB positive and negative patients in disease characteristics or severity. Similar results were obtained when SS was diagnosed in SSA/SSB positive patients.

Conclusion

RON and BON were more likely associated with abnormal autoantibodies; furthermore, AQP4 antibody, SSA/SSB and SS were more common in the RON patients. AQP4 antibodydetermination is crucial in RON patients who will develop NMO. However, when compared with other autoantibodies, SSA/SSB detected in patients was not significantly associated with disease characteristics or severity.

Differential expression pattern of microRNAs in CD4+ and CD19+ cells from asymptomatic patients with systemic lupus erythematosus

OBJECTIVE

The aim of this study was to investigate the pattern of microRNA (miRNA) expression in CD19+ and CD4+ cells from asymptomatic patients with systemic lupus erythematosus (SLE).

METHODS

A screening of the expression of 377 miRNAs was performed in human CD4+ and CD19+ cells isolated from the peripheral blood by using a TaqMan Human MicroRNA Array. Validation of differential expression pattern of those was performed using TaqMan assays in these cell populations obtained from a larger cohort of patients and controls.

RESULTS

According to the screening assays, three miRNAs were differentially expressed (p value <0.1) in cell populations from both patients and controls: hsa-miR-143, hsa-miR-224 and hsa-miR-576-5p for CD4+ cells, and hsa-miR-10a, hsa-miR-31 and hsa-miR-345 for CD19+ cells. After validation, significant differences (p value <0.05) were confirmed only for hsa-miR-143 and hsa-miR-224 in CD4+ cells and for hsa-miR-10a and hsa-miR-345 in CD19+ cells. In all cases, the miRNAs were over expressed in SLE patients compared with healthy donors.

CONCLUSIONS

Our results support a different pattern of miRNA expression in SLE patients.

Clinical and laboratory manifestations of yemeni patients with systemic lupus erythematosus

OBJECTIVES

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterised by multi-systemic involvement. This is the first study undertaken to determine the relationships between serological marker positivity and age, gender, signs and symptoms, risk factors and the treatment of SLE in Yemen.

METHODS

We investigated the cases of 149 patients with SLE admitted to Al-Thawra Hospital in Sana'a city between November 2009 and November 2010. Of the 149 patients, females represented 75.2% and males, 24.8%.

RESULTS

The most frequent presenting signs and symptoms were fatigue (84.6%), fever (81.9%), arthropathy (81.2%), anaemia (64.4%), photosensitivity (54.4%), renal involvement (53%), malar rash (52.3%), and alopecia (49%). Antinuclear antibodies (ANA) were detected in 95.3% of the patients and were associated significantly with most clinical presentations, except weight loss, hypertension and serositis. Anti-ds deoxyribonucleic acid (anti-dsDNA) was detected in 59.7% of the patients, and was associated significantly with fever and fatigue. Anti-Smith (anti-Sm) antibodies were detected in 27.5% of the patients, but were not significantly associated with all clinical presentations. Social stress was the most important risk factor for inducing SLE, with an odds ratio (OR) of 6.0, followed by common exposure to sunlight (OR = 2.2).

CONCLUSION

In this study, SLE was more prevalent among females and young adults. The clinical presentation was characterised by a high incidence of fatigue and fever, and a low incidence of oral ulcers and serositis. ANA was associated with most clinical presentations except weight loss, hypertension, and serositis. Anti-dsDNA antibodies were most frequently associated with fever, fatigue and hypertension. There was no significant association of the anti-Sm antibodies with any clinical presentations.

Candidate gene identification for systemic lupus erythematosus using network centrality measures and gene ontology

Systemic lupus erythematosus (SLE) commonly accredited as “the great imitator” is a highly complex disease involving multiple gene susceptibility with non-specific symptoms. Many experimental and computational approaches have been used to investigate the disease related candidate genes. But the limited knowledge of gene function and disease correlation and also lack of complete functional details about the majority of genes in susceptible locus, encumbrances the identification of SLE related candidate genes. In this paper, we have studied the human immunome network (undirected) using various graph theoretical centrality measures integrated with the gene ontology terms to predict the new candidate genes. As a result, we have identified 8 candidate genes, which may act as potential targets for SLE disease. We have also carried out the same analysis by replacing the human immunome network with human immunome signaling network (directed) and as an outcome we have obtained 5 candidate genes as potential targets for SLE disease. From the comparison study, we have found these two approaches are complementary in nature.

Interferon-α abrogates the suppressive effect of apoptotic cells on dendritic cells in an in vitro model of systemic lupus erythematosus pathogenesis

OBJECTIVE

An increased incidence of apoptotic cells and an increased activation of dendritic cells (DC) may be involved in the pathogenesis of systemic lupus erythematosus (SLE). We investigated the characteristics of apoptotic neutrophils and monocyte-derived DC of patients with SLE, their interaction, and the influence of autoantibodies and inflammatory cytokines on this interaction.

METHODS

Kinetics of neutrophil apoptosis and DC activation were studied by flow cytometry. To analyze the interaction of apoptotic cells with phagocytes, crossover coculture experiments were performed with DC from patients with SLE and apoptotic Jurkat T cells as well as with apoptotic neutrophils from patients with SLE and the monocytic cell line U937. SLE serum and cytokines were added to this coculture, and activation and suppression of DC were quantified by levels of inflammatory cytokine secretion.

RESULTS

Apoptotic neutrophils and DC from patients with SLE showed no inherent defects compared to healthy controls, and the suppressive nature of their interaction was not affected. Autoantibodies as well as the inflammatory cytokines interleukin 17 (IL-17) and IL-1β had no influence on the interaction in this setup. Interferon (IFN)-α, however, substantially reduced the suppressive effect of apoptotic cells on DC.

CONCLUSION

The data suggest that aberrant immune reactivity in SLE is not generally due to an intrinsic defect in apoptotic cells, their processing, or their interaction with DC, but likely arises from the milieu in which this interaction takes place. Our study highlights the importance of IFN-α during early stages of SLE and its potential as a therapeutic target.

The X chromosome and immune associated genes

The X chromosome is known to contain the largest number of immune-related genes of the whole human genome. For this reason, X chromosome has recently become subject of great interest and attention and numerous studies have been aimed at understanding the role of genes on the X chromosome in triggering and maintaining the autoimmune aggression. Autoimmune diseases are indeed a growing heath burden affecting cumulatively up to 10% of the general population. It is intriguing that most X-linked primary immune deficiencies carry significant autoimmune manifestations, thus illustrating the critical role played by products of single gene located on the X chromosome in the onset, function and homeostasis of the immune system. Again, the plethora of autoimmune stigmata observed in patients with Turner syndrome, a disease due to the lack of one X chromosome or the presence of major X chromosome deletions, indicate that X-linked genes play a unique and major role in autoimmunity. There have been several reports on a role of X chromosome gene dosage through inactivation or duplication in women with autoimmune diseases, for example through a higher rate of circulating cells with a single X chromosome (i.e. with X monosomy). Finally, a challenge for researchers in the coming years will be to dissect the role for the large number of X-linked microRNAs from the perspective of autoimmune disease development. Taken together, X chromosome might well constitute the common trait of the susceptibility to autoimmune diseases, other than to explain the female preponderance of these conditions. This review will focus on the available evidence on X chromosome changes and discuss their potential implications and limitations.

Environmental exposure, estrogen and two X chromosomes are required for disease development in an epigenetic model of lupus

Systemic lupus erythematosus (SLE) is an autoimmune disease primarily afflicting women. The reason for the gender bias is unclear, but genetic susceptibility, estrogen and environmental agents appear to play significant roles in SLE pathogenesis. Environmental agents can contribute to lupus susceptibility through epigenetic mechanisms. We used (C57BL/6xSJL)F1 mice transgenic for a dominant-negative MEK (dnMEK) that was previously shown to be inducibly and selectively expressed in T cells. In this model, induction of the dnMEK by doxycycline treatment suppresses T cell ERK signaling, decreasing DNA-methyltransferase expression and resulting in DNA demethylation, overexpression of immune genes Itgal (CD11a) and Tnfsf7 (CD70), and anti-dsDNA antibody. To examine the role of gender and estrogen in this model, male and female transgenic mice were neutered and implanted with time-release pellets delivering placebo or estrogen. Doxycycline induced IgG anti-dsDNA antibodies in intact and neutered, placebo-treated control female but not male transgenic mice. Glomerular IgG deposits were also found in the kidneys of female but not male transgenic mice, and not in the absence of doxycycline. Estrogen enhanced anti-dsDNA IgG antibodies only in transgenic, ERK-impaired female mice. Decreased ERK activation also resulted in overexpression and demethylation of the X-linked methylation-sensitive gene CD40lg in female but not male mice, consistent with demethylation of the second X chromosome in the females. The results show that both estrogen and female gender contribute to the female predisposition in lupus susceptibility through hormonal and epigenetic X-chromosome effects and through suppression of ERK signaling by environmental agents.

Reduced serum concentrations of 25-hydroxy vitamin D in Egyptian patients with systemic lupus erythematosus: relation to disease activity

BACKGROUND

Recently, vitamin D deficiency has been implicated as a potential environmental factor triggering some autoimmune disorders, including systemic lupus erythematosus (SLE)). In addition, patients with SLE, especially those with increased disease activity, were suggested to have decreased vitamin D level, suggesting that vitamin D might play a role in regulating autoantibody production.

MATERIAL/METHODS

To assess 25 hydroxy vitamin D [25(OH)D] status in Egyptian patients with SLE and its relation to disease activity. Clinical evaluation and assay of serum 25(OH)D, total calcium, phosphorous, alkaline phosphatase (ALP) and parathyroid hormone (PTH) were done on 60 SLE patients in comparison to 60 matched-healthy subjects. Serum 25(OH)D levels <30 and 10 ng/ml were defined as vitamin D insufficiency and deficiency, respectively.

RESULTS

Serum 25(OH)D was significantly lower in patients than in controls (26.33 ± 12.05 vs. 42.66 ± 9.20 respectively, p < 0.0001), with 13.30% and 60% being deficient and insufficient, respectively. Serum 25(OH)D levels were lower with increased disease activity (p = 0.03) and frequency of photosensitivity(p = 0.02) and photoprotection (p = 0.002). Systemic lupus erythematosus disease activity index (SLEDAI) score (OR: 2.72, 95% CI: 1.42-5.18, P = 0.002), photosensitivity (OR: 3.6, 95% CI: 1.9-6.8, P < 0.01) and photoprotection (OR: 6.7, 95% CI: 2.9-8.8, P < 0.001) were significant predictors of 25(OH)D level among SLE cases.

CONCLUSIONS

Low vitamin D status is prevalent in Egyptian SLE patients despite plentiful exposure to sunlight throughout the year, and its level is negatively correlated to disease activity. Future studies looking at a potential role of vitamin D in the pathophysiology and treatment of SLE are warranted.

Association of herpes zoster infection with clinical characteristics and MBL2 gene polymorphisms in Chinese children with systemic lupus erythematosus

OBJECTIVES

In the first part of this study, we analyzed clinical factors associated with pediatric-onset systemic lupus erythematosus (SLE), and patient susceptibility to herpes zoster (HZ). In the second part of this study, we characterized MBL2 genotype polymorphisms in pediatric-onset SLE patients and their possible associations with HZ.

METHODS

This 10-year prospective cohort study compared pediatric-onset SLE patients from Taiwan with and without histories of HZ. By using 2 years as a standard interval, patients with early-onset and late-onset of HZ were compared. MBL2 gene polymorphisms in exon 1 at codon 54, and in the promoter at the position -221 and -550, were tested immediately after patient enrollment.

RESULTS

We initially enrolled 98 SLE patients, and analyzed complete clinical characteristics of 82 patients (35 patients with HZ, 47 patients without HZ). The incidence of HZ was higher in SLE patients who had methylprednisolone pulse therapy, cyclophosphamide pulse therapy, and received higher cumulative steroid dose (P < 0.05 for all 3). There were no significant associations of HZ with MBL2 genotype or serum level of mannose-binding lectin.

CONCLUSIONS

Pediatric-onset SLE patients were highly susceptible to HZ, with an incidence of 35.7%. Patients given steroid, cyclophosphamide, and high cumulative steroid dose were more likely to have had HZ. Deficiency of serum mannose-binding lectin and MBL2 gene polymorphism were not associated with HZ.

Enhanced transcript levels of CD48 in CD4⁺ T cells from systemic lupus erythematosus patients

It is known that CD48 regulates T-cell activation. We evaluated the transcriptional expression of CD48 in CD4⁺ T cells from 30 SLE patients and 30 healthy controls. CD48 mRNA levels were considerably higher in the patients group: 1.80 ± 1.41 versus 1.10 ± 0.50 (p=0.023). An inverse correlation was obtained with respect to CD48 mRNA levels and age in the control group (r= -0.478, p=0.007). None association was found between CD48 mRNA expression and levels of anti-dsDNA, complement, or lymphocyte counts. Alternatively, a statistically significant positive correlation was observed between CD48 transcript levels and SLEDAI values (r=0.372, p=0.042). The higher CD48 mRNA levels observed in CD4⁺ T cells from SLE patients and the positive correlation found with SLEDAI lead us to infer that an overexpression of the protein coded by this gene may have important consequences on the development of SLE.

Transgenic overexpression of anti-double-stranded DNA autoantibody and activation of Toll-like receptor 4 in mice induce severe systemic lupus erythematosus syndromes

Systemic lupus erythematosus (SLE) is a multi-organ autoimmune disease characteristized by the presence of autoantibodies against double-stranded DNA (anti-dsDNA) in sera at high levels. Bacterial infections in SLE are associated with higher morbidity and mortality. Our goal was to observe the interaction between these 2 factors in the pathogenesis of lupus. We generated transgenic mice with monoclonal anti-dsDNA to investigate the development of lupus. By challenging the mice in vitro and in vivo with Toll-like receptor 4 (TLR4) ligand lipopolysaccharides (LPS), we were able to examine the role of bacterial infection in SLE. In our study, the transgenic mice with a secreted form of anti-dsDNA were found to have higher levels of anti-nuclear antibodies, anti-dsDNA, blood urea nitrogen, and proteinuria. The splenocytes of the mice stimulated with LPS secreted more anti-dsDNA, IFN-γ, and IL-10. After injecting them with LPS in vivo, we further found higher immune complex depositions and IL-10 in the kidneys of the transgenic mice. Moreover, the LPS-injected transgenic mice had higher mortality rate. This is the first transgenic model to demonstrate that only 2 risk factors, pathogenic anti-dsDNA and TLR4 activation, induce severe SLE syndromes in normal mice through the overproduction of IL-10 and IFN-γ. These findings imply that anti-dsDNA and bacterial infections have pivotal roles in the pathogenesis of SLE; the inhibition of TLR4 may be regarded as a therapeutic target.

IgG anti-pentraxin 3 antibodies in systemic lupus erythematosus

OBJECTIVE

To evaluate the prevalence and correlates of anti-pentraxin 3 (PTX3) antibodies in systemic lupus erythematosus (SLE).

METHODS

Serum samples from 130 patients with SLE, 130 age- and sex-matched healthy subjects and 130 patients with other autoimmune rheumatic diseases (oARD) were analysed by home-made ELISAs using as substrate human recombinant PTX3 and two peptides, PTX3_1 and PTX3_2, obtained from the complete protein, identified as potential antigenic sites using the Lasergene DNA program (DNA Star). Inhibition tests were performed to evaluate potential interferences between bovine serum albumin or C-reactive protein and anti-PTX3 or anti-PTX3 peptides, and between antigens and antibodies. Statistical analysis was performed using receiving operating characteristics curves, the Fisher exact test, two-tailed t test and Pearson correlations.

RESULTS

Patients with SLE had higher levels and prevalence of anti-PTX3, anti-PTX3_1 and anti-PTX3_2 antibodies than patients with oARD or healthy controls (p<0.001 for all). No differences were observed between patients with oARD and healthy controls. A correlation was found between anti-PTX3 and anti-PTX3_2 antibodies (r=0.615, p<0.001). No association was observed between these antibodies and disease activity. Univariate and multivariate analyses showed that anti-PTX3 and anti-PTX3_2 antibody levels and prevalence were higher in patients without glomerulonephritis and in patients positive for antiphospholipid antibody. All inhibition tests were negative apart from PTX3 against anti-PTX3 antibody or, to a lesser extent, against anti-PTX3_2 antibody, and PTX3_2 against anti-PTX3_2 antibody, all in a dose-dependent manner.

CONCLUSIONS

Anti-PTX3 antibodies are significantly prevalent in patients with SLE where they might provide protection from renal involvement. The antigenic properties of PTX3_2 peptide are similar to those of PTX3, suggesting its potential use in further analyses.

Early growth response transcription factors and the modulation of immune response: implications towards autoimmunity

Early Growth Response (EGR) zinc finger transcription factors are induced under diverse mitogenic signals on different cell types such as lymphocytes. Their genetic expression does not require de novo protein synthesis, which suggests its role as immediate response mediators between cell surface receptor signaling and gene expression regulation. EGR factors are involved in modulating the immune response, by means of the induction of differentiation of lymphocyte precursors, activation of T and B cells, as well as their involvement in central and peripheral tolerance. The maturation state, particularly for B cells, and signaling through the T or B cell receptors seems to be quite relevant for the induction of the expression of these transcription factors. EGR-1 functions as a positive regulatory factor for B and T cells mediated by transcriptional regulation of key cytokines and costimulatory molecules, and its interaction with NFAT. On the opposite, EGR-2 and 3 act as negative regulators involved in anergy induction and apoptosis. EGR-2 and 3 deficiency has been related to the development of lupus like disease in murine models. The deficiency of these transcription factors has been associated to deficient Cbl-b expression, a resistant to anergy phenotype, and expansion of effector and activated T cells.

Shared and unique gene expression in systemic lupus erythematosus depending on disease activity

Patients presenting with active systemic lupus erythematosus (SLE) manifestations may exhibit distinct pathogenetic features in relation to inactive SLE. Also, cDNA microarrays may potentially discriminate the gene expression profile of a disease or disease variant. Therefore, we evaluated the expression profile of 4500 genes in peripheral blood lymphocytes (PBL) of SLE patients. We studied 11 patients with SLE (seven with active SLE and four with inactive SLE) and eight healthy controls. Total RNA was isolated from PBL, reverse transcribed into cDNA, and postlabeled with Cy3 fluorochrome. These probes were then hybridized to a glass slide cDNA microarray containing 4500 human IMAGE cDNA target sequences. An equimolar amount of total RNA from human cell lines served as reference. The microarray images were quantified, normalized, and analyzed using the R environment (ANOVA, significant analysis of microarrays, and cluster-tree view algorithms). Disease activity was assessed by the SLE disease activity index. Compared to the healthy controls, 104 genes in active SLE patients (80 repressed and 24 induced) and 52 genes in nonactive SLE patients (31 induced and 21 repressed) were differentially expressed. The modulation of 12 genes, either induced or repressed, was found in both disease variants; however, each disease variant had differential expression of different genes. Taken together, these results indicate that the two lupus variants studied have common and unique differentially expressed genes. Although the biological significance of the differentially expressed genes discussed above has not been completely understood, they may serve as a platform to further explore the molecular basis of immune deregulation in SLE.

Incidence and nature of infectious disease in patients treated with anti-TNF agents

Tumor necrosis factor alpha (TNF-alpha) inhibitors offer a targeted therapeutic strategy that contrasts with the nonspecific immunosuppressive agents traditionally used to treat most inflammatory diseases. These biologic agents have had a significant impact in ameliorating the signs and symptoms of inflammatory rheumatoid disease and improving patient function. From the onset of clinical trials, a central concern of cytokine blockade has been a potential increase in susceptibility to infections. Not surprisingly, a variety of infections have been reported in association with the use of TNF-alpha inhibitor agents. In particular, there is evidence suggesting an increased rate of granulomatous infections in patients treated with monoclonal TNF-alpha inhibitors. This review provides the incidence and nature of infections in patients treated with TNF-alpha inhibitor agents and reminds the clinician of the required vigilance in monitoring patients.

Female predominance and X chromosome defects in autoimmune diseases

It is known that autoimmune diseases cumulatively affect 5-10% of the general population. Although knowledge of pathogenesis has become more refined, laboratory diagnosis more accurate, and therapy more effective, the reasons for the female preponderance of these conditions remain unclear. The most intriguing theory to explain the female preponderance is currently related to sex chromosomes, as women with autoimmune diseases manifest a higher rate of circulating cells with a single X chromosome (i.e. X monosomy). In addition, there have been several reports on the role of X chromosome gene dosage through inactivation or duplication in autoimmunity. Taken together, sex chromosome changes might constitute the common trait of the susceptibility to autoimmune diseases.